In western Ireland, a series of basic rocks injected and replaced by migmatitic gneiss is found between the Galway granite and the migmatized rocks in Connemara. It has previously been postulated by Burke that the migmatites are the result of interaction between the Galway granite and its envelope. Evidence from more recent mapping seems to indicate that the Galway granite postdates the Connemara migmatization. Such an interpretation would be in line with a radioactive age of 365 million years. Six new chemical analyses of granite are given.

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